Replace USE_LOCAL_HEADERS with USE_INTERNAL_*

code/sys/sys_loadlib.h

@@ -35,7 +35,7 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #		define Sys_LibraryError() dlerror()
 #	endif
 #else
-#	ifdef USE_LOCAL_HEADERS
+#	ifdef USE_INTERNAL_SDL_HEADERS
 #		include "SDL.h"
 #		include "SDL_loadso.h"
 #	else

code/sys/sys_local.h

@@ -24,7 +24,7 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #include "../qcommon/qcommon.h"
 
 #ifndef DEDICATED
-#ifdef USE_LOCAL_HEADERS
+#ifdef USE_INTERNAL_SDL_HEADERS
 #	include "SDL_version.h"
 #else
 #	include <SDL_version.h>

code/sys/sys_main.c

@@ -36,7 +36,7 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #endif
 
 #ifndef DEDICATED
-#ifdef USE_LOCAL_HEADERS
+#ifdef USE_INTERNAL_SDL_HEADERS
 #	include "SDL.h"
 #	include "SDL_cpuinfo.h"
 #else